At present, compared with the transformer power source, the inverter of the microwave oven draws much attention of customers because of its advantages of lightweight, high power factor and continuously adjustable power. However, the inverter consists of numbers of electronic elements, and electronic parameters of each electronic element have errors, such that for the same input different inverters may output powers that greatly deviate from the actual value.
Because of such property, when producing a microwave oven with frequency conversion function on the production line, it needs to adjust the full power (P100) of the microwave oven, such that the user may use the microwave oven with a normal power. However, the microwave oven also has other power magnitudes, such as P90 (90% of the full power), P80 (80% of the full power), P70 (70% of the full power), P60 (60% of the full power), P50 (50% of the full power). It is significantly important to adjust these power magnitudes to normal ranges, while P100 is adjusted to a normal power.
The conventional solution for above problem is that, by using a computer board controller, a coefficient weighted correction is applied to a level to be adjusted based on the reference power so as to form a final power, thus adjusting the difference of the power. However, since the relationships between different powers are nonlinear, it is difficult to determine the weighted correction coefficient. Moreover, such solution may cause the power magnitudes outputted by different inverters exceeding the normal fluctuation range of the power.